x2xxx: fixed getStopBit() and getTransmitReceiveMode() redefinition typo...

I migrated my development from msp430-int branch to tp-master and found out that probably merging from tinyos-main has broken x2xx Usci.

Here is my manual merge that I did some time ago: https://github.com/andresv/prod/commit/42fa931b8abcf772cedd3648d114b1c0d04b160d